scpi-dmm: run OPC queries immediately before essential commands

[libsigrok.git] / src / hardware / scpi-dmm / protocol.c

diff --git a/src/hardware/scpi-dmm/protocol.c b/src/hardware/scpi-dmm/protocol.c
index 954e6c98feaf983be9c269508bfba88d6c291135..717c30daaaf688fd67638e9cf8e02736c5073760 100644 (file)
--- a/src/hardware/scpi-dmm/protocol.c
+++ b/src/hardware/scpi-dmm/protocol.c
@@ -90,12 +90,12 @@ SR_PRIV int scpi_dmm_get_mq(const struct sr_dev_inst *sdi,
        if (mqitem)
                *mqitem = NULL;
 
+       scpi_dmm_cmd_delay(sdi->conn);
        command = sr_scpi_cmd_get(devc->cmdset, DMM_CMD_QUERY_FUNC);
        if (!command || !*command)
                return SR_ERR_NA;
        response = NULL;
        ret = sr_scpi_get_string(sdi->conn, command, &response);
-       scpi_dmm_cmd_delay(sdi->conn);
        if (ret != SR_OK)
                return ret;
        if (!response || !*response)
@@ -140,10 +140,12 @@ SR_PRIV int scpi_dmm_set_mq(const struct sr_dev_inst *sdi,
 
        mode = item->scpi_func_setup;
        command = sr_scpi_cmd_get(devc->cmdset, DMM_CMD_SETUP_FUNC);
-       ret = sr_scpi_send(sdi->conn, command, mode);
        scpi_dmm_cmd_delay(sdi->conn);
+       ret = sr_scpi_send(sdi->conn, command, mode);
+       if (ret != SR_OK)
+               return ret;
 
-       return ret;
+       return SR_OK;
 }
 
 SR_PRIV int scpi_dmm_get_meas_agilent(const struct sr_dev_inst *sdi, size_t ch)
@@ -267,8 +269,8 @@ SR_PRIV int scpi_dmm_get_meas_agilent(const struct sr_dev_inst *sdi, size_t ch)
        command = sr_scpi_cmd_get(devc->cmdset, DMM_CMD_QUERY_VALUE);
        if (!command || !*command)
                return SR_ERR_NA;
-       ret = sr_scpi_get_string(scpi, command, &response);
        scpi_dmm_cmd_delay(scpi);
+       ret = sr_scpi_get_string(scpi, command, &response);
        if (ret != SR_OK)
                return ret;
        g_strstrip(response);