Agilent EPM Series 437B and 438A Compatibility Application Note
Table of Contents 3 3 3 4 4–5 6 6 7 7 7 8 8 8 9–10 11 11–12 12 13 13 14 15 16–17 18–19 1. Introduction 2. Physical Compatibility 3. Sensor Compatibility 4. Language Compatibility 4.1 Zeroing and calibrating 4.2 Measurement mode selection 4.3 Range hold and manual ranging 4.4 Limits 4.5 Filter 4.6 Duty cycle, window offsets, sensor calibration tables, and frequency dependent offset tables 4.7 Channel offsets for the E4419A/B dual channel power meter 4.8 Preset 4.9 Measurement errors 4.
1. Introduction 2. Physical Compatibility The Agilent Technologies EPM series power meters, introduced in 1997, are the successors to the 43X family of power meters. A large number of 437B and 438A power meters are used in Automated Test Equipment (ATE) environments. In order to substitute the EPM series power meters in an ATE system or rack, the EPM series has been designed to fit into the same rack space as the 437B and 438A. For this reason, the EPM series power meters are the same width (212.6 mm; 8.
. Language Compatibility The Agilent E4418A/B with 437B language compatibility mode selected can systematically replace a 437B power meter in an existing application. Similarly the E4419A/B can replace the 438A power meter. Please note that the E4419A must have firmware revision A.02.02 or higher in order to have 438A language compatibility.
Or: 100 OUTPUT @Pm;”CS;ZE” 110 OUTPUT @Pm;”SM” 120 ENTER @pm;$Message 130 IF $Message[5,6] = “06” THEN GOTO 110 ! Clear status register and initiate zero ! Request status message ! Wait until zero completes (06 means zeroing) Or: 100 OUTPUT @Pm;”CS;AE;ZE” ! Clear status register and initiate channel A zero 110 OUTPUT @Pm;”SM” ! Request status message 120 ENTER @pm;$Message 130 IF $Message[5,6] = “06” ! Wait until zero completes THEN GOTO 110 (06 means ChA zeroing) 200 OUTPUT @Pm;”CS;CL100EN” ! Clear stat
4.2 Measurement mode selection The 437B and 438A have certain delays associated with measurement mode changes and auto ranging. Some software may have made use of this feature to allow, for example, some other instrument to settle before triggering the power meter. Such assumptions cannot be made for the Agilent EPM series power meters, as they are much faster and more responsive. A typical scenario for the E4419A/B dual channel power meter is discussed below.
4.4 Limits The over and under limits checking functions used in the 438A perform exactly the same way in the E4419A/B. The only function that the E4419A/B does not support is the “over high limit” and “under low limit.” This is because the E4419A/B does not allow the high limit threshold to be less than the lower limit threshold, which this particular function requires. Software using this feature will require a work around. The 437B and 438A allow upper and lower limits of +/-299.
4.7 Channel offsets for the E4419A/B dual channel power meter Prior to entering 438A language or after a localto-remote transition while in 438A language, the E4419A/B channel offset state and level will be altered as follows: • If the channel offset is OFF and the level is not 0 dB, then the level will be set to 0 dB. 4.9 Measurement errors Measurement errors can occur for a variety of reasons, but it is worth being aware of the error reporting methods used by the 437B and 438A.
4.10 Using the Agilent E-series power sensors The E-series power sensors (E4412A and E4413A) can only be used with EPM series power meters and cannot be used with the 437B or 438A power meters. However, the E-series sensors can be used with the EPM series power meters in 437B and 438A language mode. Due to the fact that the E-series sensors have calibration factors stored in sensor EEPROM, the sensor calibration factor and reference calibration factor commands are no longer valid.
When using an E-series sensor in 438A language, the FR (frequency) command will be accepted. The syntax for this command is shown below. FR 100E+03 to 999.99E+09 HZ KZ MZ GZ Note: Sending this command when the active entry channel is connected to an 8480 series sensor will cause a syntax error. The Agilent E-Series sensors have an upper and lower range and are affected by the ranging commands as detailed below.
4.11 Recorder output The recorder output on the 437B or 438A would normally be used with manual ranging and produces an analog output level (0 to +1 volts) that is proportional to the power level being measured. This voltage level is scaled relative to the minimum and maximum power levels for the current range. The EPM series power meter has one continuous range.
• Window selection: The highlighted window on the E4419A/B display is equivalent to what would be shown on the 438A. Sometimes it may be beneficial to have just the highlighted window shown. This command allows either a single or dual window display. 4.13 Must calibrate/zero The E4418B and E4419B power meters have a “Must cal/zero” feature. This feature can be enabled to prevent measurements being made until the connected sensor is zeroed and calibrated.
4.14 Sources and analyzers Some Agilent signal generators and network analyzers use a 437B power meter for flatness and leveling. The EPM series power meter can be used in place of a 437B/438A with the following products: • Signal generators: 83732A, 83752A, 83600 series • Network analyzers: 8753, 8710, 8510 series 4.
The following cases are known problems when using the E4419A or E4419B dual channel power meter in 438A language compatibility mode. Having triggered the meter, the same effect can be obtained by addressing the meter to talk and waiting for the response. The result will not be returned until the measurement cycle has completed. 1.
6. Summary Replacing the 437B and 438A with the new Agilent Technologies EPM series of power meters should be a simple process. However, as this application note has highlighted, there are some issues that users may encounter. The information given here should help to resolve these issues. For more details on the EPM series power meters, please contact your local Agilent sales office for EPM series power meter literature.
Appendix A: 437B Command Summary This table details all the 437B commands that the Agilent E4418A and E4418B support and the command function. For a detailed description of these commands please refer to the 437B Power Meter Operating Manual.
Command Description Command Description LN Linear units (watts/%) RT1 Right arrow key LP2 Learn mode RV Read service request mask LT1 Left arrow key SE Select sensor calibration table MZ Megahertz SM Status message OC0 Reference oscillator off SN Enter sensor identification/serial number OC1 Reference oscillator on SP1 Special OD Output display SPD 20 | 402 OF0 Offset off *SRE Set the service request mask OF1 Offset on *SRE? Service request mask query OS Enter offset
Appendix B: 438A Command Summary This table details all the 438A commands that the Agilent E4419A and E4419B support and the command function. For a detailed description of these commands please refer to the 438A Operating and Service Manual.
Command Description RM Set measurement range RV Read service request mask SM Status message SPD 20 | 402 ST Store (save) power meter configuration SYST:LANG SCPI3 Selects SCPI language TR0 Trigger hold TR1 Trigger immediate TR2 Trigger with delay TR3 Trigger free run ZE Zero @1 Prefix for status mask ?ID Identification query 1. This command is accepted but has no active function. 2. This command is not an original 438A command.
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