The SRM-5A, manufacted by RAD, is an asynchronous modem used for local communication between a data logger and a computer. Two SRM-5A Short Haul Modems are required: one at the data logger end and one at the computer end. Each short haul modem transmits over an unconditioned 4-wire telephone line or the CABLE2TP two-twisted pair cable. Data rates up to 9,600 bps are possible.Read More
Campbell Scientific recommends connecting the SRM-5A to the data logger's CS I/O port via the SC932A interface; a 9-to-25 pin adapter is required. It may be possible to connect the SRM-5A to the data logger's RS-232 port, but configuration is more complicated; contact Campbell Scientific for more information. Surge protectors on both ends of the transmission line are strongly recommended.
|Data Rates||Up to 9,600 bps|
|Transmission Mode||Asynchronous, full duplex, 4-wire operation|
|Transmission Distance or Area||Up to 12.2 km (7.6 mi) depending on data rate and wire gage|
|Line Interface||5-screw (4-wire and ground) connector block with cable strain relief inside plastic cover|
|Transmission Line||CABLE2TP (for short RS-232 or prewired enclosures) or unconditioned, 4-wire telephone line|
|Transmission Level||6 dBm|
|Terminal Interface||EIA RS-232-C/CCITT V.24, female integral 25-pin connector|
|Operating Temperature Range||0° to 60°C (Manufacturer's temperature specification is listed. Limited tests conducted by Campbell Scientific have shown the SRM-5A to perform at temperatures over -25° to +50°C.)|
|Current Drain at 12 Vdc||
|Altitude||Up to 3,000 m (10,000 ft)|
|Humidity||Up to 95% (non-condensing)|
|Service Requirements||Dedicated two-twisted pair cable connects one field station with base.|
|Dimensions||5.2 x 5.2 x 1.8 cm (2.1 x 2.1 x. 0.7 in.)|
|Weight||38 g (1.3 oz)|
Note: The following shows notable compatibility information. It is not a comprehensive list of all compatible or incompatible products.
|CR9000X (retired)||Although the CR9000X is compatible, the SRM-5A does not support the CR9000X's maximum communication rate and therefore may not be practical for many CR9000X applications.|
The SRM-5A is compatible with the now retired SRM-6A; the two can be used on either end of the same line.
Most manufacturers refer to cables compatible with this application as "PE39 Cable".
|Company||Part Number||AWG||Shield Type||Rodent Proof|
.005 Copper Clad Stainless Steel
|Company||Part Number||Outer Jacket||Messenger|
|Anixter||F-02P19AAF||19 HMW Polyethylene||.109 extra high strength steel|
Additional hardware is required to hang cables; contact your local Anixter representative for details.
Number of FAQs related to SRM-5A: 7
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Campbell Scientific does not currently offer any.
Technically, the SRM-5A is compatible with the CR200X-series dataloggers, but it is more complicated to use it with these data loggers. To use a SRM-5A with a CR200X-series datalogger, the SRM-5A must be in the DTE position on the station modem. In addition, user-supplied adapters and gender changers are needed to complete the connections between the SRM-5A and the RS-232 port of the data logger. Contact Campbell Scientific for more information.
It is not cost effective to repair. The SRM-5A should be replaced.
Use the terminal mode of the Device Configuration Utility (select Unknown for Device type) set to 9600 baud. Click the Connect button to open the terminal screen.
On the SRM-5A, short together the RCV + to the XMT +, and the RCV – to the XMT – connections. Try typing letters and numbers with the computer keyboard. If these do not appear on the terminal screen, the modem is damaged and must be replaced. Ensure that the Echo Input box is NOT selected.
If connecting to the CS I/O port, one of the following is needed:
A connection can also be made to the RS-232 port. However, the switch on the SRM-5A must be in the DTE position on the station modem, and adapters and gender changers may be needed to complete the connection.