Detcon 10B - Manual (Page 8)

2 2..4 4..7 7 T Te esstt M Mo od de e
This function (tE) will cause a simulation of applying a full scale gas sample that will take the display through an incre-
mental count up to the top of the range and back down, activating alarms at the programmed set points and allowing
verif ication of alarm outputs, as well as the overange f lashing feature.
2.5 P
OWER
I
NPUT
O
PTIONS
Standard operating input power of the Model 10 control module is 24 VDC unless 12 VDC is specified at time of order. All of
the circuitry of the Model 10 control module, with the exception of relays, will operate on 12 or 24 VDC.
A 24 VDC control module can be converted to a 12 VDC control module by changing the relays. If this is desired, it is
recommended that the control modules be returned to Detcon to be converted. However, if technical personnel are
used, the 24 VDC relays (OMRON #G6B-2114P-US-DC24) may by replaced by 12 VDC relays (OMRON ##G6B-2114P-
US-DC12) at the owner’s discretion. Caution: note that the only identif ication for required input power is the labeling
on the alarm relays.
2.6 A NALOG 4-20 M A S IGNAL I NPUT /O UTPUT
The Model 10 receives an analog 4-20 mA signal input and converts it to the specif ied range of detection. The signal is
processed through an analog to digital converter and is calibrated so that a 4 mA input will provide a display readout of
“0” and a 20 mA input will provide a display readout equal to full-scale range. This circuitry is factory set. Should
adjustment become necessary, refer to the controller calibration section (section 2.10).
2.7 RS-485 M ODBUS ™ F EATURES AND S PECIFICATIONS
Model 10 control modules feature Modbus™ compatible communications protocol and are addressable via the pro-
gramming menu for multi-point communications. Communication is two wire, half duplex, with the Model 10 control
module set up as a slave device. A master controller up to 4000 feet away can theoretically poll up to 256 different
Model 10 control module cards. This number may not be realistic in harsh environments where noise and/or wiring
conditions would make it impractical to place so many devices on the same pair of wires. If a multi-point system is
being utilized, each control module should be set for a different address. Typical address settings are: 01, 02, 03, 04, 05,
06, 07, 08, 09, 0A, 0B, 0C, 0D, 0E, 0F, 10, 11, etc.
Model 10 control module ID numbers are set via the programming menu as described in section 2.4.1.
The following register list describes the parameters available from the Model 10 control module:
40000 Range
40001 Reading
40002 Alarm 1 Set Point
40003 Alarm 2 Set Point
40004 Not Used
2.8 F
AULT
C
IRCUIT
F
UNCTIONS
Model 10 control modules feature fail safe supervisory circuits designed to assure maximum reliability in system perfor-
mance. A fault condition will cause the fault LED to illuminate and the fault relay to actuate. The exception to this is if
the fault relay is jumper-programmed as normally energized, a loss of external 24 VDC power or the internal 5 VDC
supply will cause the relay to de-energize but the LED will not illuminate. Below is a list of conditions that will cause a
fault alarm:
1. Loss of 24 VDC power to the Model 10 control module (only if relay is programmed as normally energized).
2. Open power loop from the control module to the gas sensor. Displayed as “OH”
3. Open signal loop from the control module to the gas sensor. Displayed as “SF”
4. When used with a Detcon TP series solid state H2S sensor — an open heater on the sensor chip. Displayed as “OH”
5. When used with a Detcon FP series combustible sensor — an open catalytic bead or bridge. Displayed as “OH”
6. Loss of the internal 5 VDC supply (only if relay is programmed as normally energized).
7. Signal level drift below 2.4 mA from the gas sensor. Displayed as “SF”
Model 10 Single Channel Digital Control Module PG.8