ICS Regent+Plus ® PD-7017 Relay Output Modules Low Power and High Power (T7446L and T7446H) Issue 1, March, 06 Relay output modules provide control of eight user output loads. Two types of relay output modules are available providing dry contact relay closure outputs for switching a variety of AC and DC voltages to field loads.
Relay Output Modules (T7446L, H) Module Operation A block diagram of a typical relay output module is shown in Figure 1. The processor modules send triplicated write data commands to the output module over the I/O Safetybus. The processors’ addressing data and data write commands are voted by the module (preventing I/O Safetybus failures upstream from the module from affecting module operation). The voted result is then passed to the I/O bus interface logic. Figure 1.
(T7446L, H) Relay Output Modules logically turned off, the relay coil is de-energized (closing the N.C. contact). The relay provides logic-to-field isolation between the module’s logic and field circuits — protecting the output module from field signal over voltages, transients, and other electrical disturbances. Both types of relay output module use UL 508 approved relays. Testing and Diagnostics Each module’s voter circuits are periodically tested by the processor modules.
Relay Output Modules (T7446L, H) Shutdown Indicator Upon loss of communications with the controller, output modules enter either a shutdown or hold fault mode. If the I/O assembly is set to shutdown, the red SHUTDOWN indicator will turn on when communications with the controller are lost. If the I/O assembly is set to hold, the SHUTDOWN indicator will always be off (see page 11, Fault Mode Jumper).
(T7446L, H) Relay Output Modules Figure 2. Relay Output Module.
Relay Output Modules (T7446L, H) Application Simplex Configuration Relay output modules provide a suitable interface to noncritical output devices. These non-critical devices typically include status alarms or other field devices that are not used for primary safety shutdown purposes. Although much of the circuitry on the relay output module is automatically tested, some logic circuits and the field-side output switch are simplex and non-tested. This simplex configuration is illustrated in Figure 3.
(T7446L, H) Relay Output Modules Relay Operation The relays used on the T7446L contain SPDT contacts. For the Form-A or Form-B selectable outputs, a jumper in the module is used to select Form-A (N.O.) or Form-B (N.C.) action. The relays used on the T7446H contain two SPST contacts (one normally closed and one normally open). Jumpers within the module are also used to select the relay form. On the Form-C output, there is no guarantee for make-before-break or break-before-make.
Relay Output Modules (T7446L, H) Figure 4. Jumper Locations. Operating Envelope Figure 5 shows the voltage and current operating envelopes for the T7446L and T7446H. The T7446L relays are initially gold clad and have an initial resistance of 50 mOhm maximum. However, operation at high voltages and currents will remove the gold and the closed resistance will increase substantially. This increased resistance reduces its ability to subsequently switch very low power loads.
(T7446L, H) Relay Output Modules As with any relay, operating at higher voltages and currents will result in decreased relay life. Figure 6 shows the voltage and current versus service life for the relays. Figure 5. Voltage and Current Operating Envelopes.
Relay Output Modules (T7446L, H) 100000 10000 1000 100 10 0 0.4 0.8 1.2 1.6 2 2.4 0 0.4 0.8 1.2 1.6 2 2.4 100000 10000 1000 100 10 Figure 6. Voltage and Current vs. Service Life. Relay Protection Each relay circuit must be fused externally to protect the relay and the load. Modules are also fused internally with factory-replaceable fuses to protect the I/O assembly and the module’s printed circuit board.
(T7446L, H) Relay Output Modules Fault Mode Jumper The fault mode jumper is located behind the ID switch cover in the lower left-hand corner of each I/O chassis. The position of the fault mode jumper determines the module's response to system level faults. The fault mode jumper’s position will cause all output modules in the I/O chassis to either shutdown (turn off all outputs) or to hold (hold the last state) after a system level failure occurs.
Relay Output Modules (T7446L, H) Figure 7. Installing Slot Keys. Configuration Each output module is configured using the WINTERPRET I/O Configuration Editor. In the editor you will perform the three steps described below to configure the output module.
(T7446L, H) Relay Output Modules 1) Set the Module Type: Position the cursor on the module slot you wish to define. Choose Set Module Type from the Edit Menu and select the relay output module from the list. 2) Edit the Module Definition: Choose Edit Module Definition from the Edit Menu. A dialog box will open where you can define the output point definitions. Figure 8. Relay Output Module Definition.
Relay Output Modules (T7446L, H) Name Also called the tag name, this is the name used in the application program to reference the output point. The name can be up to 12 characters long. Description This 40-character field provides a place to describe the output point definition. The description is used to help document your system (it does not affect application program operation).
(T7446L, H) Relay Output Modules control logic by using a contact element (or similar element) with the output point name. Maintenance No periodic maintenance or calibration is required for this module. If a module is to be replaced, verify the replacement module’s relay form configuration matches the original relay output module. Fuses for each output are located inside the module. These fuses are for protection of the I/O chassis connectors and module circuit board only, and are not field-replaceable.
Relay Output Modules (T7446L, H) Specifications Safetybus Power 1.0 load units Number of Outputs Eight isolated circuits (four Form-C contacts, four selectable N.O. or N.C. contacts) Voltage Range Load Current Minimum Load Surge Current Over Voltage Protection T7446L 0.1 to 125 VAC/DC 2.0 amps 0.1 VDC/10 mA 20 amps, 16 msec T7446H 5 to 250 VAC 5 to 125 VDC 2.0 amps 5 VDC/10 mA 20 amps, 16 msec 750 VAC, 1 minute 1000 VAC, 1 minute 110 VAC, 0.3 amps 24 VDC, 1 amp 110 VAC, 0.2 amps 24 VDC, 0.
(T7446L, H) Relay Output Modules Fusing (internal) Operating Temperature One 3.5 A, slow blow per output Note: Internal fuses are for protection of the printed circuit board only. Each output should be individually fused outside the module with a fuse rated for the output load. 0° to 60° C (32° to 140° F) Storage Temperature -40° to 85° C (-40° to 185° F) Operating Humidity 0 to 95% relative humidity, non-condensing Vibration 10 to 55 Hz: ±0.
Relay Output Modules (T7446L, H) 18 Industrial Control Services
