Section 3
ZGARD C 1-Channel Controller
General Information
OPERATING SPECIFICATIONS
Remote Sensor Input
1 only, 4-20mA analogue, 2 or 3wire
OR
RS485 digital data bus, 4-wire connection
Remote Sensor Power
24Vdc at 100mA / Input
Network Capacity
1 Remote Gas Sensor
Power Requirements
(Optional)
Standard 110Vac, 50/60 Hz ± 10% at 0.15 Amps
220Vac, 50/60 Hz ± 10% at 0.10 Amps; 24Vdc
±
10% at 0.5 Amps
Temperature
Operating: -10° to 40°C (14° to 104°F); Storage: -20° to 50°C (-4° to 122°F)
LED Readout
1 + 3 Digit LED display exhibits the channel number and gas level, at 2 second intervals
Status LED Indicators
Power, Warning, Alarm and Sensor OK
Audible Alarm
Electronic device, 93 dB @ 0.3 meters with variable sound selection
Pushbutton
Alarm reset and Silence function
Alarm & Warning Set points
Factory set at 35% and 50% Full-Scale, unless otherwise specified (Field Adjustable)
Sensor Fail Set point
Non-adjustable
Time Delays
Fixed 5 minutes ON delay for Alarm and 5 minutes OFF delay for Warning
or
manually
adjusted from 0 to10 minutes
Relay Outputs
Warning Relay, Alarm Relay and Sensor Fail Relay: Form C - SPDT
Relay Action
Alarm Relay Latching or Non-Latching, jumper selected
Relay Contacts Rating
10 Amps 1/8 H.P., 125Vac, 5 Amps, 30Vdc, 6 Amps 1/8 H.P., 277Vac
(Optional) Signal Output
4-20mA analogue output
Enclosure
(Optional)
Metal NEMA 1
Fiberglass NEMA 4X design
Dimensions
11.5” H (292 mm) x 10” W (254 mm) x 3.75” D (95 mm)
Weight
4.5kg (10 lbs.)
Certification
ENTELA (to CSA Standards)
Sensor Input:
The ZGARD C 1-Channel controller
accepts 1 remote gas sensor. The MSA ZGARD S or
GS, 4-20mA 2 or 3-wire analogue or RS485 type
sensor. The RS485 serial communication sensors are
automatically recognized by the controller and establish
the sensor range and gas code type.
Readout:
LED display exhibits the corresponding sensor
gas concentration level.
Warning and Alarm Set Points:
The Warning and Alarm
threshold levels are independently adjustable on the
controller and can be set to any value between 0 and
100% Full-Scale (FS).
Delay Function:
There are two user jumper selected
methods for setting the ZGARD C 1-Channel controller
warning and alarm delays. The first uses pre-
programmed, fixed delays of 5 minutes OFF delay for
warning and 5 minutes ON delay for alarm. The second
allows adjusting of the delays from 0 to 10 minutes using
potentiometers.
Warning and Alarm Scheme:
During a Warning event,
the Warning (Amber) LED will turn on and the warning
relay will be activated. No audible alarm is set off at this
time. Once a warning occurrence has been abated, the
associated warning LED will turn off and the warning
relay will be deactivated. If the 5 minute delay feature is
selected, then this action takes place after a 5 minute
delay period. During an Alarm event, the associated
Alarm (Red) LED will turn on and the alarm relay will be
activated. If the 5 minute delay feature is selected and the
alarm event has prolonged for a period of 5 minutes, then
the alarm relay will be activated and the audible device
will sound. Pressing the reset button on the front panel
will silence the audible device. Once the alarm
occurrence has been abated, the audible device will
silence (if not silenced already by reset button) and the
alarm relay will be deactivated. If any other active
channels reach the alarm state, the audible device will
sound with every new alarm event. Once all of the active
channels have been cleared of alarm events, the audible
device will silence (if not silenced already by reset button)
and the alarm relay will be deactivated.
Sensor Fail:
If an analog sensor is used and the input is
between 1mA and 3.5mA, the Sensor OK LED will turn
off and the Sensor Fail Relay will be activated. Any
analog input below 1.0mA causes the controller to ignore
that analog input and treat that sensor as an RS485 type
sensor. If there is a lose of communication between the
controller and the remote gas sensor residing on the
RS485 network, the Sensor Fail Relay will be activated
and the Sensor OK LED will turn off.
Optional 4-20mA Output:
The analogue output
continuously represents the signal generated by the
remote sensor output.
3.0