Specifications

Setup & SetUp Command 5-7
High Alarm Latch
Bit 5 determines whether the HI Alarm is latching or momentary. A’1'
indicates latching. Bit 5 is also controlled individually by the HI Alarm (HI)
command.
Disable CJC
RTD 3/4 Wire
Trigger Edge Select
The setup information stored in bit 4 has different meanings depending on
the D1000 model number.
Disable CJC; this function pertains only to the D1300 series of thermo-
couple input modules. If the bit is set to ‘1’ the Cold Junction Compensation
is disabled. The module calculates the temperature output with a fixed cold
junction temperature of 0 degrees Celsius. This setup is useful for calibrating
the module or in cases where remote CJC is used. Normally this bit is cleared
to ‘0’.
RTD 3/4 Wire; this function pertains only to the D1400 series of RTD input
modules. If the bit is set to ‘1’, the module provides the correct lead-
compensation calculation for 4-wire RTD’s. If the bit is cleared to ‘0’, the
module calculates the correct lead compensation for 3-wire RTD’s. Meas-
urement errors may result if the module is not set to the correct sensor type.
This function has no affect on D145X or D146X Thermistor inputs.
Celsius/Fahrenheit
The default scaling for temperature output modules is Celsius which is
selected by making bit 3 = 0. To change the scaling to Fahrenheit, set bit 3
to ‘1’. All modules that do not have temperature output must have bit 3
cleared to zero. The scaling factors are operative only on the sensor data;
HI and LO limits and setpoints must be modified by appropriate commands
to reflect a scaling change (see Figure 2.1).
Echo
When bit 2 is set to ‘1’, the D1000 module will retransmit any characters it
has received on the communications line. This option is necessary to ‘daisy-
chain’ multiple RS-232C modules. Echo is optional for systems with a single
RS-232C module. Bit 2 must be cleared to ‘0’ on RS-485 models. See
Chapter 3 for a more complete description.
Delay
Bits 0 and 1 specify a minimum turn-around delay between a command and
the module response. This delay time is useful on host systems that are not
fast enough to capture data from quick-responding commands such as RD.
This is particularly true for systems that use software UART’s. The specified