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SMC sierra monitor corporation Sentry Instruction Manual - Version 6
APPENDIX H - MODEL 5100-99 ANALOG INPUT MODULE
Page: 106
8.8 APPENDIX H - MODEL 5100-99 ANALOG
INPUT MODULE
8.8.1 DESCRIPTION
The Analog Input Module is used to allow input to
Sentry by a 4-20 mA analog device, such as an
analog gas sensor or other type of sensing device.
The module has the same physical form as other
Sentry gas modules except that the sensor
assembly in the lower hub is replaced by the user’s
analog input device.
8.8.2 INSTALLATION
Figure 8-5 shows the terminal connections for the
analog input module.
• Connect channel wiring (P S G) from the
Sentry controller to TB1 in the same manner
as other sensor modules.
• For three wire analog input device:
⇒ Double up the power (P) on TB1
connection to provide 19 - 21 VDC to the
analog input device.
⇒ Connect ground (G) and signal (S) on
TB2 to the corresponding terminals on the
analog input device.
• For two wire analog input device:
⇒ Double up the power (P) on TB1 connection to
provide 19 - 21 VDC to the analog input device.
⇒ Connect signal (S) on TB2 to the corresponding
terminal on the analog input device.
8.8.3 ADJUSTMENT PROCEDURE
Prior to reading voltages and making adjustments perform
a visual inspection to confirm that there are no physical
problems such as water in the electronics enclosure,
wiring damage or corrosion.
8.8.3.1 SIGNAL ADJUSTMENT
The Model 5100-99 transmitter must be adjusted when a
new analog input is connected. It is not necessary to
perform periodic adjustment of the tranmitter, but normal
calibration of the input should be perfomred according to
manufacturer instructions.
To adjust the tranmitter:
1. Connect DVM to Signal Out and Ground test points
on the cover plate.
2. Supply 4 mA from the sensor device and adjust “Zero
Adj” potentiometer until DVM reads 0.0 VDC.
3. Supply 20 mA from the sensor device and adjust
“Span Adj” potentiometer until DVM reads 2.0 VDC.
4. Repeat steps 2 and 3 on an iteration basis until step 2
requires no further adjustment.
8.8.3.2 CALIBRATION
To calibrate the combined Model 5100-99 and analog
sensor input, follow the standard Sentry Global
Calibration instructions. See 5.3.1.1
Figure 8-5
Model 5100-99 Analog Input Component Locator