Hello. I am new to the DT80M having just returned to DT's since the DT50 era in the early 1990's.

I am developing a remote monitoring and control strategy for an Off Grid Renewable Energy solution that must have communications redundancy built into it to move at least a bit closer to a "mission critical" level of communications confidence. This is best achieved by having two different methods to communicate with the one system.

I have a DT80M and want to add an external modem to it [along with the internal modem], using either an Ethernet GSM or Serial Sensor Port GSM Modem. This might seem like an unusual requirement but it is a critical requirement for my remote communications strategy with the DT80M. I want to be able to send an SMS message to the DT80M via the external modem; then have that message string "looked up" or evaluated in the DT80M; and responded to accordingly by a returned SMS message actioned by either the external modem or the internal modem [either would be OK but maintaining the internal modem web server connectivity and continuity without interruption is important]. From a functionality example standpoint only, the SMS Message String sent TO the DT80M external modem would look something like: "SMS ME THE FOLLOWING VALUES 1CV;2CV;3CV" the DT80M Response SMS sent out would look something like this: "1CV=00001234.1234;2CV=00000018.9100;3CV=00000000.0027".

It seems that the discontinued SMSX GSM Modem went part way to providing this functionality although the documentation regarding SMS strings sent out relate to Alarm conditions rather than data Values. Being a serial modem though indicates that the DT80M Serial Sensor Port could be used for an external GSM Modem. Perhaps an Ethernet GSM Modem would even be a better option.

Is what I have described feasible and possible, and any advice at all from members would be very much appreciated.

Lawrence

Hi Lawrence,

Internal modem should be used for web server connection only while external modem could be used for SMS or web server connection.

Using internal modem for both SMS and web server at the same time might crash dataTaker.
Internal modem is using host SERIAL port and our firmware has lock the use of AT command for data connection only, therefore reconstruct AT command using internal modem to receive SMS is not possible.
SMS receive must be set using external modem.

External modem could be connected to Ethernet port (for web-server connection) and SERIAL sensor port (SMS).
You must develop several fix SMS sequences to be send to external modem and create a conditional statement and set of actions in dataTaker related to those sequences.
Then you may construct a string for detecting SMS every minute using those sequence and AT command [AT+CMGF (fax/ SMS mode), AT+CMGL (list of SMS) and AT+CMGD (delete SMS)].
dataTaker will read that sequence and compare with conditional statement to take related action.

It is recommended to use a simple single number rather than a complex string because of efficiency and easiness reason on string construction

Example:
Reading value
REFT(=1CV,W)

SMS request:
1CV

dataTaker syntax to detect an incoming SMS:

• retrieve SMS list
  2SERIAL("{AT+CMGF=1\013}\w[500]",W)
  2SERIAL("\e{AT+CMGL=\034REC UNREAD\034\013}",W)
  2SERIAL("{AT+CMGD=0,4\013}",W)

• parsing an SMS, 20$ is used to save the sender number, 9CV is used to save the number
  2SERIAL("\m[+CMGL: ]\m[\034REC UNREAD\034,\034]%12s[20$]\m[ACK]%d[9CV]\e",W)

dataTaker syntax to send a reply SMS only if 9CV is equal to 1 which mean you ask for 1CV value:
IF(9CV==1){2SERIAL("{AT+CMGF=1\013}\w[500]{AT+CMGS=\034}")}
IF(9CV==1){2SERIAL("{%s[20$]\034\013}\m[\062]{1CV= %d[1CV]\026\013}\m[CMGS]\e}")}

Best regards,
Rudy Gunawan

Thanks Rudy this is a very good heads up for us to work from.

An extension of this subject is about the useful options then available for handling "in a meaningful way" the DT80M returned SMS message string, and that really is what our system communications development project is all about, as the system integrator responsible for the ongoing maintenance and system performance management of remote location and unattended off grid energy generation plants.

And this is where Excel comes into the frame regarding its data analytics capabilities along with its real time SMS functionality [for both send and receive] from within a workbook.

I will keep the forum posted on this project.

Lawrence