Manual for SZ1143b

Brand: TCS Basys Controls

Category: Controller

Manual Type:

Language:

Uploaded: April 1, 2025, 12:48 a.m.

Manual Publish Date: 2009-08-01

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The SZ1143b operates in occupied or unoccupied mode, selectable via Digital Input 1. It uses analog inputs for 4-20mA transmitters for temperature, pressure, humidity etc. Analog outputs can modulate devices based on setpoints and input values. Digital outputs control stages of heating or cooling with configurable offsets and differentials. Programming is done via keypad or PC for parameters like setpoints, deadbands, PID control, and output configurations.

Troubleshooting and error codes

Problem Possible Cause and Solution
No Display Check for 24 VAC on terminals 24VAC "R" and GND "C".
Relay Outputs Do Not Come On Check the setpoint, deadbands, offsets and differentials. Check to be sure that the digital outputs are programmed properly for "heating" or "cooling" (make on fall, make on rise), and that they are not disabled. Short "L1/2" to "M1" to bypass digital output one, and "L1/2" to "M2" to bypass digital output two. This is a check for a mechanical relay failure.
Wrong Temperature Display If either of the two analog input readings is slightly high or low, the respective Low and High scaling limits can be adjusted slightly. Let's say that the Al1 value is 5° Low and that Al1 has a span from -40 to 160°F. Change the scaling for the Low and High scaling limits to be -35°F to 165°F, instead of -40°F to 160°F. You can also measure DC voltage from "Al1" to GND "C" and "AI2" to GND "C". The 4 to 20mA inputs are represented as 1 to 5VDC signals here. Using this knowledge, you can determine whether the problem is with the controller or your input device.
Outputs Will Not Shut Off First check the Al1 value and the setpoint and deadbands, then determine whether the output should be on. There are delays and minimum on and off times for the relay stages. Also, check the monitoring menus to verify that the digital outputs are on. Pulling the terminal with the 24VAC “R” and GND "C" wires off, will instantly turn all outputs off and reset the controller.
Analog Output Not Working Properly Check wiring. A separate transformer should be used for the SZ1143b and a separate transformer should be used for the modulating device. Check to make sure that the analog output is programmed correctly.

Troubleshooting and error codes

Problem Possible Cause and Solution
No Display Check for 24 VAC on terminals 24VAC "R" and GND "C".
Relay Outputs Do Not Come On Check the setpoint, deadbands, offsets and differentials. Check to be sure that the digital outputs are programmed properly for "heating" or "cooling" (make on fall, make on rise), and that they are not disabled. Short "L1/2" to "M1" to bypass digital output one, and "L1/2" to "M2" to bypass digital output two. This is a check for a mechanical relay failure.
Wrong Temperature Display If either of the two analog input readings is slightly high or low, the respective Low and High scaling limits can be adjusted slightly. Let's say that the Al1 value is 5° Low and that Al1 has a span from -40 to 160°F. Change the scaling for the Low and High scaling limits to be -35°F to 165°F, instead of -40°F to 160°F. You can also measure DC voltage from "Al1" to GND "C" and "AI2" to GND "C". The 4 to 20mA inputs are represented as 1 to 5VDC signals here. Using this knowledge, you can determine whether the problem is with the controller or your input device.
Outputs Will Not Shut Off First check the Al1 value and the setpoint and deadbands, then determine whether the output should be on. There are delays and minimum on and off times for the relay stages. Also, check the monitoring menus to verify that the digital outputs are on. Pulling the terminal with the 24VAC “R” and GND "C" wires off, will instantly turn all outputs off and reset the controller.
Analog Output Not Working Properly Check wiring. A separate transformer should be used for the SZ1143b and a separate transformer should be used for the modulating device. Check to make sure that the analog output is programmed correctly.